Side ejector for band saw conveyor or the like

ABSTRACT

A side ejector for a conveyor which includes an ejector bar normally extending in storage position along one side of the conveyor and which is connected at its ends to drive chains, the chains extending transversely and driven by individual reversible actuators for sweeping the bar laterally across the conveyor. To achieve substantially the same amount of stroke at each end of the bar, the actuators are supplied through a flow divider. Each actuator has a diverter valve for diverting pressure fluid into the sump upon completion of its stroke thereby to insure that the actuators remain precisely in step with one another free of any cumulative error.

United States Patent Wilkin 1451 Apr. 11, 1972 541 SIDE EJECTOR FOR BANDSAW 3,480,328 11/1969 Canlson ..91/171 CONVEYOR OR THE LIKE 3,033,2196/1962 Erie ..91/171 2,808,921 10/1957 Knowles ..l98/24 [72] M" will,Schaumburg, 3,543,644 12/1970 Stacey ..60/97 1; [73] Assignee:Armstrong-Blum Manufacturing Company, Chicago, Ill. PrimaryExaminer-Richard E. Aegerter {22] Filed: June 29 1970 Attorney--Wolfe,Hubbard, Leyd1g, Vo1t & Osann [2i] App]. No.5 50,706 [57] ABSTRACT Aside ejector for a conveyor which includes an ejector bar [52] US. Cl..l98/24, 60/97 E normally extending in storage position along one sideof the [51] Int- Cl olk 3/ g 47/00 conveyor and which is connected atits ends to drive chains, Field 0f fl 60/97 the chains extendingtransversely and driven by individual 214/1 P3, 775 reversible actuatorsfor sweeping the bar laterally across the conveyor. To achievesubstantially the same amount of stroke [56] References Cited at eachend of the bar, the actuators are supplied through a UNITED STATESPATENTS flow divider Each actuator has a diverter valve for divertingpressure flu1d into the sump upon completlon of 1ts stroke 2,343,8995/1944 thereby-to insure that the actuators remain precisely in step 1 129 1 966 with one another free of any cumulative error. 3,067,851l2/1962 1,643,714 9/ l 927 3 Claims, 10 Drawing Figures .72 I; ll 1 "11T 5 5 E1 @151 PATENTEDAPR 11 1972 3,655,025

sum u U? 6 AlfdENE/f.

SIDE EJECTOR FOR BAND SAW CONVEYOR OR THE LIKE It is an object of thepresent invention to provide a side ejector for a band saw conveyorwhich includes an ejector bar, or beam, which is swept broadwise acrossthe conveyor for discharge of an engaged workpiece into a suitablereceptacle at the side of the conveyor thereby to free the conveyor toreceive a successive workpiece. It is a related object to provide a sideejector in the form of an ejector bar, powered at its ends by separateactuators but which has means for insuring that the actuators arerestored to a reference position at the end of each power stroke so asto avoid cumulative error.

It is another object of the present invention to provide a side ejectorwhichis rapid and effective in its action and which is particularly wellsuited for remote control from a control station located at the bandsaw.

It is a more detailed object of the invention to provide an ejector barwhich cooperates with, and which is arranged in overlapping relationwith respect to a dead stop, thereby to minimize the length of conveyorrequired to provide both the dead stop and ejecting functions.

In one of the aspects of the invention it is an object to provide a sideejector in. which the ejector bar may be extended to any desired lengthsimply by addition of sections and in which means are provided forinsuring that the sections move precisely in unison with one anotherwith no possibility of cumulative error even after long periods ofoperation.

Thus it is a general object of the present invention to pro vide anejecting mechanism for a band saw conveyor which is safe and fool proofin its operation, which requires only simple control means forinitiating the ejection and return strokes from a central controlstation and which requires no special exercise of skill or judgment onthe part of the operator of the machine.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawings in which:

FIG. 1 is a plan view of a band saw and conveyor setup employinganejector for broadwise ejection of workpieces from the conveyor.

FIG. 2 is a vertical section, somewhat enlarged, taken along the line2-2 in FIG. 1.

FIG. 3 is a fragmentary section taken along the line 3-3 in FIG. 2.

FIGS. 4, and 6 are vertical sections taken along lines 44, 55 and 66respectively in FIG. 2.

FIG. 7 is a fragmentary section taken through the rack and pinion alongline 7-7 in FIG. 2.

FIG. 8 is a diagram showing the effect of the telescoping connection atone end of the ejector bar.

F IG. 9 is an hydraulic circuit diagram of a type preferred for use inpracticing the present invention.

FIG. 10 is a partial diagram corresponding to FIG. 9 showing diversion,with equalization, at the end of the eject stroke.

While the invention has been described in connection with a preferredembodiment, it will be understood that I do not intend to be limited bythe particular embodiment shown but intend, on the contrary, to coverthe various alternatives and equivalent constructions included withinthe spirit and scope of the appended claims.

Turning now to the drawings there is disclosed in FIG. 1 a band sawhaving a stationary table 21 and a reciprocable frame 22 carrying a sawblade 23, with the presented portion of the saw blade being turned sothat it lies in a plane parallel to the direction of reciprocation forcutting on the forward stroke. The band saw controls are convenientlylocated on a control console 24 at the front of the machine. At the lefthand or inlet side of the machine is a conveyor 25 which feeds a lengthof stock 26 between the jaws of a clamping vise 27 mounted on the sawtable.

On the downstream side of the saw is a conveyor 30 having longitudinalframe members 31, 32 which are preferably of channel shape and whichsupport a series of spaced rollers 33 which are journaled, at the ends,in supports 34.

For the purpose of positioning the leading end of a length of stock forcutting off a work piece to exact length, a dead stop is provided on thedownstream side as covered in my copending U.S. application Ser. No.50,532 filed concurrently herewith. The dead stop structure includes asupporting rail 40 mounting a traveling carriage 41. Hinged to thecarriage at a joint 42 is a stop member 43 having an engaged stopsurface 44 which extends across the width of the conveyor.

In operation the carriage 41 is run out to a predetermined position asindicated by noting the reading on a calibrated tape 45 which isconnected to the carriage. The carriage is then clamped to the rail. Thestock 26 is advanced into engagement with the stop surface 44, the vise27 is clamped shut to hold the stop in position, and the cut is made.The stop member 43 is then retracted slightly along the axis of thehinge 42 and rocked upwardly clear of the severed workpiece which canthen be advanced into the position shown at 26a in readiness forejection.

In accordance with the present invention an ejector bar, or beam,normally extending in a storage position along one side of the conveyor,is coupled at its ends to ejector chains which are powered by individualreversible actuators by a multiplying rack and pinion coupling. Thusreferring to FIGS. 1-7, an ejector bar 50 is provided which occupies astorage position along the near edge of the conveyor and which has eyeconnections 51, 52 at its ends secured to chain drive assemblies 55, 56.For engaging the eye 51 of the bar the chain assembly 55 includes atransverse slide 60 mounted between ways 61, 62 and having an upwardlyextending pin 63 which is fitted into the eye 51. The slide 60 has apair of depending, spaced-apart brackets 64, 65. To drive the slidetransversely of the conveyor a chain is used which is trained about adriving sprocket 71 mounted upon a shaft 72 journaled in bearing plates73, 74 (FIG. 6). Horizontally alined with the top of the drive sprocket71 is an idler sprocket 75 mounted upon a shaft 76, the ends of whichare secured in the way members 61, 62 (FIG. 4) and with a tension takeup adjustment 77. For guiding the lower run of the chain a second idlersprocket 78 is provided mounted upon a shaft 79 which is supported inpillow blocks 81, 82 having adjusting or take up screws 83. The chainpasses between the depending brackets 64, 65 on the slide 60 and ispinned to the latter by pins 85. Proper spacing between the way members61, 62 is maintained by a bridge 86 which is connected between them.

For the purpose of driving the shaft 72 to provide multiplication ofstroke, a reversible actuator 90 is used having fluid connections 91, 92and a rack 93 which engages a small diameter pinion 94 which is integralwith the shaft 72. The rack is maintained in mesh with the pinion by aback-up roller 95 which is mounted on a shaft 96.

It will be apparent, then referring to FIG. 2, that when the actuator 90is pressurized to elevate the rack 93, pinion 94 rotates the sprocket 71counterclockwise so that the slide 60, which is connected to the chain,sweeps across the width of the conveyor from the storage position to thedotted discharge position. Because of the substantial difference betweenthe pitch diameter of the pinion 94 and the effective diameter of thesprocket 71, stroke multiplication is achieved on the order of 39am 1,thereby insuring sufficient travel of the ejector bar using a relativelycompact actuator with limited upward projection of the rack 93 when theactuator is fully extended. Corresponding structure 56 is employed atthe other end of the bar 50 for operation in unison, corresponding partsbeing assigned the same reference numerals, where applicable, withaddition of subscript a.

For the purpose of insuring that both ends of the ejector bar are movedprecisely in step with one another and without any cumulative error, aflow divider of the positive or metering type is interposed in thehydraulic circuit leading to the actuators, with a diverter valve, whichis actuated at the end of the stroke, for diverting the pressure fluidso that both actuators are free to achieve a reference position at theend of each stroke, thereby insuring that the actuators remain in stepand precluding development of cumulative error over a series of strokes.Thus referring to FIG. 9 which shows the preferred form of hydrauliccircuit, a pump P, driven by a motor M, draws fluid from a sump S.Connected to the output of the pump and to the sump line is a four wayvalve 100 having connections 101, 102 and connections 103, 104controlled by a spool 105. The connection 104 feeds a flow divider 110having an inlet" connection 111 and outlet" connections 112, 112a. Thefluid divider will be recognized as a commercially available productconsisting, in effect, of two gear sets 113, 113a of the type employedin a gear pump and with their shafts mechanically coupled together by amechanical connection indicated at 114. Because of the mechanicalconnection, equal amounts of fluid are metered to both of the actuators90, 90a so that they operate in unison to produce substantially equalstrokes. There is always the possibility, however, that a little morefluid, in this case oil or the like, may leak past one of the sets ofgears I13, 113a than the other so that upon passage of time one of theactuators will tend to bottom ahead of the other. This would beundesirable since once bottoming occurs in one of the actuators rotationof the gears is stopped and fluid cannot be fed to the other actuator inorder to enable it to catch up".

Accordingly a diverter valve 120 is provided having oppositely facingcheck valves 121, 122 and with means for unseating one of the checkvalves, to permit diversion to the sump, of pressure fluid around theactuator which is the first to bottom at the end of the stroke. In thepresent instance the unseating means is in the form of a lever 123 whichis engaged by a pin 124 on the rack 93 for unseating of the check valve121. When the check valve 121 is open the connections 91, 92 of theactuator 90 are effectively connected together. Thus the diverter valve120 may be considered to create a short circuit" around the actuator.

Let is be assumed that the valve 100 is in the condition shown so thatequal metered amounts of fluid are fed to the lower connections of thetwo actuators 90, 90a, but suppose that the actuator 90 tends to bottomat its upper end slightly ahead of the actuator 90a. Bottoming isaccompanied by the striking of the lever 123 by the pin 124 on the rack,thereby unseating the ball 121 so that any fluid thereafter furnished tothe actuator 90 is not trapped but simply diverted to the sump, as shownin FIG. 10, thereby permitting the flow divider to condition where thelatter actuator is the first one to bottom at either end of the stroke.It is particularly important that both of the actuators be allowed tocomplete their downward strokes to insure that the ejector bar isretracted fully into its storage position along one side of the conveyorsince it must, in such position, register with spaced notches, indicatedat 43a in FIG. 2, which are formed on the underside of the stop member43. This overlapping of the ejector bar with the dead stop enables longworkpieces to be handled by the conveyor while keeping the conveyor downto a reasonable length.

The automatic repositioning in reference position brought about by thediverter valves at the end of each stroke not only prevents thedevelopment of any cumulative positioning error but also enables use ofa less precise and hence less expensive flow divider, resulting in asaving which will substantially pay for the added cost of the divertervalves. Moreover, because of the diverter valves, the system is immuneto the effects of leakage which may develop in any flow divider over aperiod of time. The resultant system not only achieves synchronousmovement at the ends of the ejector bar but is substantially foolproof,requiring little or no maintenance over long periods of time.Nevertheless, because of the residual possibility of failure in one halfof the system, means are provided for percontinue to operate and tofurnish fluid until bottoming also occurs in the actuator 90a. Thus bothends of the ejector bar will be positioned in an outer referenceposition for return, in step with another, on the return stroke to thestorage position.

For initiating the return stroke the spool of the valve 100 is manuallyreversed so that pressure fluid exists at the connection 103 and so thatfluid is returned to the sump via connection 104. This causes both ofthe actuators to be pressurized for movement of the racks downwardly andfor corresponding retracting movement of the chains. However in thismode of operation the outlet and inlet functions are reversed. That is,the flow divider, instead of metering pressurized fluid from the pump,serves to meter return flow of fluid from the connections 91, 91a of theactuators backwardly into the sump. In the event that the actuator 90 isthe first to bottom in the downward direction, this would, normally,block further movement in the flow divider to prevent fluid from beingfully discharged from the actuator 90a to preventing it from completingits downward stroke. Therefore to continue furnishing of fluid to theleft hand side of the flow divider, to permit it to continue to operate,even though the actuator 90 is bottomed, a second diverter valve 130 isprovided having check valves 131, 132 therein and with the valve 131being unseated by a lever 133 engaged by the pin 124 at the lowerextreme of the actuator stroke. This effectively diverts fluid aroundthe actuator 90 so that fluid continues to be supplied to the connection112 of the flow divider until the fluid from the lower end of theactuator 90a is completely discharged. t

The above discussion has assumed that it is the actuator 90 which is thefirst to bottom. Corresponding diverter valves 120a, 130a are providedfor actuator 90a to take care of the mitting effective elongation of theejector bar to accommodate the canted condition. This is brought aboutby providing a telescoping joint 52a at the end of the ejector bar 50 asshown in FIG. 8 the tenn telescoping connection as used herein refers toany connection which accommodates elongation of the distance between theconnection points at the ends of the bar.

Where pieces are to be ejected which are longer than the ejector bar 50a third chain drive assembly may be provided similar to the unit shownin FIGS. 2-7 along with another section of bar 50, the two sections thusbeing arranged end to end for movement by a total of three chain driveunits. The only changes necessary where this is done are the provisionof a third actuator with its additional diverter valves and substitutionof a flow divider having three sets of gears and three outputconnections. In the same way the system can be extended to four or moresections.

While the use of two diverter valves with each of actuators has beendiscussed for achieving a reference position at the ends of both theejection and retraction strokes, a single diverter valve, effective onlyupon completion of, say, the retraction stroke, may be used. Stated inother words, it would be possible to achieve adequate referencing byusing only the diverter valves 130, 130a while dispensing with thevalves 120, a. Also, while the invention has been discussed inconnection with a mechanically triggered diverter valve, referencing maybe also achieved by use of a relief valve which is set somewhat higherthan the pressure normally attained at the actuators without departingfrom the invention. For example relief valves could be interposed in thesystem at the connections 92, 92a set at a pressure slightly higher thanthe normal operating pressure. As the first one of the actuators bottomsin the downward direction, the resulting increase in back pressure wouldopen the associated relief valve, freeing the gears for additionalrotation, for flow of additional fluid to the tardy actuator, permittingthe latter to advance and join the first actuator in the retractedreference position.

The use of a diverter valve with each actuator, mechanically operated asthe actuator moves into its bottomed condition, is preferred because ofthe greater force which then becomes available at the tardy actuator.The reason for this is that the pair of flow divider gears which areunloaded when diversion occurs operate as a gear motor, applying torquethrough the shaft 114 to the gears associated with the tardy actuator toaugment the pressure applied to the latter thereby to insure completebottoming in spite of the presence of obstructing forces.

While the device, as described, ejects workpieces at the backside of theconveyor, it may be employed with equal efficiency for ejection ofworkpieces at the front, whereupon the fully shifted position of the bar50 would become the home position, without requiring any change in theejector construction. However, for front ejection it would be necessaryeither to switch the stop gage support to the opposite side of theconveyor or to elongate the conveyor so that the ejection station is ata downstream position beyond the stop gage with no overlap.

I claim as my invention:

1. In an ejector for ejecting a lengthy workpiece broadwise followingcutoff in a band saw or the like, the combination comprising a conveyorextending downstream from the band saw, an ejector bar having a storageposition in which it extends along one side of the conveyor, the ejectorbar having an extensive pushing surface for parallel surface engagementof workpieces of different length, means providing first and secondloops of chain extending transversely of the conveyor and coupled to therespective ends of the ejector bar, first and second reversibleactuators, means including a rack and pinion connection for coupling theactuators to the chains, means including a reversing valve for applyingpressure fluid to one end of said actuators for movement of the ejectorbar from its storage position to its ejecting position and for apply ingpressure fluid to the opposite end of the actuators for restoring theejector bar to its storage position, a positive metering type flowdivider interposed between the reversing valve and the actuators formetering fluid to and from the actuators in substantially equal amountsfor substantially equal movement of the ejector bar at its ends, adiverter valve associated with each of the actuators for diverting thepressure fluid applied to the associated actuator upon completion of theactuator stroke so that in the event one actuator completes its strokebefore the other the flow divider may continue to operate until thesecond actuator also completes its stroke thereby to insure the returnof each end of the ejector bar fully to a storage reference position.

2. In an ejector for ejecting a lengthy workpiece broadwise followingcut-off in a band saw or the like, the combination comprising a conveyorextending downstream from the band saw, an ejector bar having a storageposition in which it extends along one side of the conveyor, meansproviding first and second loops of chain trained about spaced sprocketsand extending transversely of the conveyor and coupled to the ends ofthe ejector bar, first and second reversible fluid actuators, each ofsaid actuators having a rack and small diameter rack pinion with thepinions being coupled to sprockets of the respective chains formultiplying the stroke of the chains with respect to the stroke of theactuators, a source of pressure fluid, means including a flow dividerhaving its input connected to the source of pressure fluid and itsoutputs connected respectively to the actuators for achieving equalizedmovements of the chains, the flow divider being of the type having apair of gear sets mechanically coupled together for rotation in unisonfor metering of equal amounts of fluid to the outputs, and meanseffective upon the bottoming of one of the actuators for diverting fluidtherefrom to enable continued operation of the flow divider untilbottoming occurs in the other actuator.

3. In an ejector for ejecting a lengthy workpiece broadwise followingcut-off in a band saw or the like, the combination comprising a conveyorextending downstream from the band saw, a dead stop extendingtransversely of the conveyor, an ejector bar having a storage positionin which it extends along one side of the conveyor, the dead stop beingpositionable between the chain drive assemblies and recessed to bridgethe ejector bar when the latter is in storage reference position, thedead stop being rockable upwardly out of the way of the ejector bar,first and second chain drive assemblies presenting first and secondloops of chain extending transversely of the conveyor and coupled to therespective ends of the ejector bar, first and second reversibleactuators, means including rack and pinion connections for coupling theactuators to the chains, means including a reversing valve for applyingpressure to one end of said actuators for movement of the e'ector barfrom its storage position to its e ecting position and or applyingpressure fluid to the opposite end of the actuators for restoring theejector bar to its storage position, a positive metering type flowdivider interposed between the reversing valve and type flow dividerinterposed between the reversing valve and the actuators for meteringfluid to and from the actuators in substantially equal amounts forsubstantially equal movement of the ejector bar at its ends, a diverterassociated with each of the actuators for diverting the pressure fluidapplied to the associated actuator upon completion of the actuatorstroke so that in the event one actuator completes its stroke before theother the flow divider may continue to operate until the second actuatoralso completes its stroke thereby to insure the return of each end ofthe ejector bar fully to the storage reference position.

1. In an ejector for ejecting a lengthy workpiece broadwise followingcutoff in a band saw or the like, the combination comprising a conveyorextending downstream from the band saw, an ejector bar having a storageposition in which it extends along one side of the conveyor, the ejectorbar having an extensive pushing surface for parallel surface engagementof workpieces of different length, means providing first and secondloops of chain extending transversely of the conveyor and coupled to therespective ends of the ejector bar, first and second reversibleactuators, means including a rack and pinion connection for coupling theactuators to the chains, means including a reversing valve for applyingpressure fluid to one end of said actuators for movement of the ejectorbar from its storage position to its ejecting position and for applyingpressure fluid to the opposite end of the actuators for restoring theejector bar to its storage position, a positive metering type flowdivider interposed between the reversing valve and the actuators formetering fluid to and from the actuators in substantially equal amountsfor substantially equal movement of the ejector bar at its ends, adiverter valve associated with each of the actuators for diverting thepressure fluid applied to the associated actuator upon completion of theactuator stroke so that in the event one actuator completes its strokebefore the other the flow divider may continue to operate until thesecond actuator also completes its stroke thereby to insure the returnof each end of the ejector bar fully to a storage reference position. 2.In an ejector for ejecting a lengthy workpiece broadwise followingcut-off in a band saw or the like, the combination comprising a conveyorextending downstream from the band saw, an ejector bar having a storageposition in which it extends along one side of the conveyor, meansproviding first and second loops of chain trained about spaced sprocketsand extending transversely of the conveyor and coupled to the ends ofthe ejector bar, first and second reversible fluid actuators, each ofsaid actuators having a rack and small diameter rack pinion with thepinions being coupled to sprockets of the respective chains formultiplying the stroke of the chains with respect to the stroke of theactuators, a source of pressure fluid, means including a flow dividerhaving its input connected to the source of pressure fluid and itsoutputs connected respectively to the actuators for achieving equalizedmovements of the chains, the flow divider being of the type having apair of gear sets mechanically coupled together for rotation in unisonfor metering of equal amounts of fluid to the outputs, and meanseffective upon the bottoming of one of the actuators for diverting fluidtherefrom to enable continued operation of the flow divider untilbottoming occurs in the other actuator.
 3. In an ejector for ejecting alengthy workpiece broadwise following cut-off in a band saw or the like,the combination comprising a conveyor extending downstream from the bandsaw, a dead stop extending transversely of the conveyor, an ejector barhaving a storage position in which it extends along one side of theconveyor, the dead stop being positionable between the chain driveassemblies and recessed to bridge the ejector bar when the latter is instorage reference position, the dead stop being rockable upwardly out ofthe way of the ejector bar, first and second chain drive assembliespresenting first and second loops of chain extending transversely of theconveyor and coupled to the respective ends of the ejector bar, firstand second reversible actuators, means including rack and pinionconnections for coupling the actuators to the chains, means including areversing valve for applying pressure to one end of said actuators formovement of the ejector bar from its storage position to its ejectingposition and for applying pressure fluid to the opposite end of theactuators for restoring the ejector bar to its storage position, apositive metering type flow divider interposed between the reversingvalve and type flow divider interposed between the reversing valve andthe actuators for metering fluid to and from the actuators insubstantially equal amounts for substantially equal movement of theejector bar at its ends, a diverter associated with each of theactuators for diverting the pressure fluid applied to the associatedactuator upon completion of the actuator stroke so that in the event oneactuator completes its stroke before the other the flow divider maycontinue to operate until the second actuator also completes its strokethereby to insure the return of each end of the ejector bar fully to thestorage reference position.